common/kmdb/kmdb_module_load.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/param.h>
#include <sys/modctl.h>
#include <sys/kobj.h>
#include <sys/kobj_impl.h>
#include <unistd.h>
#include <strings.h>
#include <dlfcn.h>
#include <link.h>

#include <kmdb/kmdb_module.h>
#include <kmdb/kmdb_wr_impl.h>
#include <kmdb/kmdb_kdi.h>
#include <mdb/mdb_modapi.h>
#include <mdb/mdb_debug.h>
#include <mdb/mdb_string.h>
#include <mdb/mdb_ctf.h>
#include <mdb/mdb_err.h>
#include <mdb/mdb_io.h>
#include <mdb/mdb_frame.h>
#include <mdb/mdb.h>

static void kmdb_module_request_unload(kmdb_modctl_t *, const char *, int);

static void
kmc_free(kmdb_modctl_t *kmc)
{
    if (kmc->kmc_modname != NULL)
        strfree(kmc->kmc_modname);
    mdb_free(kmc, sizeof (kmdb_modctl_t));
}

/*
 * Sends a request to the driver to load the module.  If/when the load has
 * completed successfully, kmdb_module_loaded is called.
 */
int
mdb_module_load(const char *fname, int mode)
{
    const char *modname = strbasename(fname);
    kmdb_wr_load_t *dlr;
    kmdb_modctl_t *kmc = NULL;
    const char *wformat = NULL;
    mdb_var_t *v;

    if (!mdb_module_validate_name(modname, &wformat))
        goto module_load_err;

    if ((v = mdb_nv_lookup(&mdb.m_dmodctl, modname)) != NULL) {
        kmc = MDB_NV_COOKIE(v);

        if (kmc->kmc_state == KMDB_MC_STATE_LOADING)
            wformat = "module %s is already being loaded\n";
        else
            wformat = "module %s is being unloaded\n";
        goto module_load_err;
    }

    kmc = mdb_zalloc(sizeof (kmdb_modctl_t), UM_SLEEP);
    kmc->kmc_loadmode = mode;
    kmc->kmc_modname = strdup(modname);
    kmc->kmc_state = KMDB_MC_STATE_LOADING;

    if (mdb_nv_insert(&mdb.m_dmodctl, modname, NULL, (uintptr_t)kmc, 0) ==
        NULL) {
        wformat = "module %s can't be registered for load\n";
        kmc_free(kmc);
        goto module_load_err;
    }

    dlr = mdb_zalloc(sizeof (kmdb_wr_load_t), UM_SLEEP);
    dlr->dlr_node.wn_task = WNTASK_DMOD_LOAD;
    dlr->dlr_fname = strdup(fname);

    kmdb_wr_driver_notify(dlr);

    if (!(mode & MDB_MOD_DEFER) &&
        mdb_tgt_continue(mdb.m_target, NULL) == 0)
        return (0);

    if (!(mode & MDB_MOD_SILENT))
        mdb_printf("%s load pending (:c to complete)\n", modname);

    return (0);

module_load_err:
    if (!(mode & MDB_MOD_SILENT))
        warn(wformat, modname);

    return (-1);
}

int
kmdb_module_loaded(kmdb_wr_load_t *dlr)
{
    struct modctl *modp = dlr->dlr_modctl;
    const char *modname = strbasename(dlr->dlr_fname);
    struct module *mp;
    kmdb_modctl_t *kmc;
    mdb_var_t *v;

    v = mdb_nv_lookup(&mdb.m_dmodctl, modname);

    if (dlr->dlr_errno != 0) {
        /*
         * We're somewhat limited in the diagnostics that we can
         * provide in the event of a failed load.  In most load-failure
         * cases, the driver can only send up a generic errno.  We use
         * EMDB_ENOMOD to signal generic errors, and supply our own
         * message.  This twists the meaning of EMDB_NOMOD somewhat, but
         * it's better than defining a new one.
         */
        if (dlr->dlr_errno == EMDB_NOMOD) {
            mdb_warn("%s does not appear to be a kmdb dmod\n",
                modname);
        } else {
            (void) set_errno(dlr->dlr_errno);
            mdb_warn("dmod %s failed to load", modname);
        }

        if (v != NULL)
            mdb_nv_remove(&mdb.m_dmodctl, v);
        return (0);
    }

    if ((mp = modp->mod_mp) == NULL || mp->symhdr == NULL ||
        mp->strhdr == NULL || mp->symtbl == NULL || mp->strings == NULL) {
        mdb_warn("dmod %s did not load properly\n");
        goto module_loaded_err;
    }

    if ((v = mdb_nv_lookup(&mdb.m_dmodctl, modname)) == NULL) {
        kmc = mdb_zalloc(sizeof (kmdb_modctl_t), UM_SLEEP);
        kmc->kmc_loadmode = MDB_MOD_LOCAL;
        kmc->kmc_modname = strdup(modname);
        kmc->kmc_state = KMDB_MC_STATE_LOADING;

        (void) mdb_nv_insert(&mdb.m_dmodctl, modname, NULL,
            (uintptr_t)kmc, 0);
    } else {
        kmc = MDB_NV_COOKIE(v);
        ASSERT(kmc->kmc_symtab == NULL);
    }

    kmc->kmc_modctl = modp;
    kmc->kmc_exported = (mp->flags & KOBJ_EXPORTED) != 0;
    mdb_gelf_ehdr_to_gehdr(&mp->hdr, &kmc->kmc_ehdr);

    kmc->kmc_symtab = mdb_gelf_symtab_create_raw(&kmc->kmc_ehdr, mp->symhdr,
        mp->symtbl, mp->strhdr, mp->strings,
        MDB_TGT_SYMTAB);

    if (mp->flags & KOBJ_PRIM)
        kmc->kmc_flags |= KMDB_MC_FL_NOUNLOAD;

    if (mdb_module_create(modname, modp->mod_filename,
        kmc->kmc_loadmode, &kmc->kmc_mod) < 0)
        goto module_loaded_err;

    kmc->kmc_state = KMDB_MC_STATE_LOADED;

    return (1);

module_loaded_err:
    if (kmc->kmc_symtab != NULL)
        mdb_gelf_symtab_destroy(kmc->kmc_symtab);

    kmdb_module_request_unload(kmc, kmc->kmc_modname, MDB_MOD_DEFER);
    return (0);
}

void
kmdb_module_load_ack(kmdb_wr_load_t *dlr)
{
    strfree(dlr->dlr_fname);
    mdb_free(dlr, sizeof (kmdb_wr_load_t));
}

void
mdb_module_load_all(int mode)
{
    kmdb_wr_t *wn;

    ASSERT(mode & MDB_MOD_DEFER);

    wn = mdb_zalloc(sizeof (kmdb_wr_t), UM_SLEEP);
    wn->wn_task = WNTASK_DMOD_LOAD_ALL;

    kmdb_wr_driver_notify(wn);
}

void
kmdb_module_load_all_ack(kmdb_wr_t *wn)
{
    mdb_free(wn, sizeof (kmdb_wr_t));
}

static void
kmdb_module_request_unload(kmdb_modctl_t *kmc, const char *modname, int mode)
{
    kmdb_wr_unload_t *dur = mdb_zalloc(sizeof (kmdb_wr_unload_t), UM_SLEEP);
    dur->dur_node.wn_task = WNTASK_DMOD_UNLOAD;
    dur->dur_modname = strdup(modname);
    dur->dur_modctl = kmc->kmc_modctl;

    kmdb_wr_driver_notify(dur);

    kmc->kmc_state = KMDB_MC_STATE_UNLOADING;

    if (!(mode & MDB_MOD_DEFER) &&
        mdb_tgt_continue(mdb.m_target, NULL) == 0)
        return;

    if (!(mode & MDB_MOD_SILENT))
        mdb_printf("%s unload pending (:c to complete)\n", modname);
}

/*ARGSUSED*/
int
mdb_module_unload(const char *name, int mode)
{
    kmdb_modctl_t *kmc = NULL;
    const char *basename;
    mdb_var_t *v;

    /*
     * We may have been called with the name from the module itself
     * if the caller is iterating through the module list, so we need
     * to make a copy of the name.  If we don't, we can't use it after
     * the call to unload_common(), which frees the module.
     */
    name = strdup(name);
    basename = strbasename(name);

    /*
     * Make sure the module is in the proper state for unloading.  Modules
     * may only be unloaded if they have properly completed loading.
     */
    if ((v = mdb_nv_lookup(&mdb.m_dmodctl, basename)) != NULL) {
        kmc = MDB_NV_COOKIE(v);
        switch (kmc->kmc_state) {
        case KMDB_MC_STATE_LOADING:
            warn("%s is in the process of loading\n", basename);
            return (set_errno(EMDB_NOMOD));
        case KMDB_MC_STATE_UNLOADING:
            warn("%s is already being unloaded\n", basename);
            return (set_errno(EMDB_NOMOD));
        default:
            ASSERT(kmc->kmc_state == KMDB_MC_STATE_LOADED);
        }

        if (kmc->kmc_flags & KMDB_MC_FL_NOUNLOAD)
            return (set_errno(EMDB_KMODNOUNLOAD));
    }

    if (mdb_module_unload_common(name) < 0) {
        if (!(mode & MDB_MOD_SILENT)) {
            mdb_dprintf(MDB_DBG_MODULE, "unload of %s failed\n",
                name);
        }
        return (-1); /* errno is set for us */
    }

    /*
     * Any modules legitimately not listed in dmodctl (builtins, for
     * example) will be handled by mdb_module_unload_common.  If any of
     * them get here, we've got a problem.
     */
    if (v == NULL) {
        warn("unload of unregistered module %s\n", basename);
        return (set_errno(EMDB_NOMOD));
    }

    ASSERT(kmc->kmc_dlrefcnt == 0);

    mdb_gelf_symtab_destroy(kmc->kmc_symtab);

    kmdb_module_request_unload(kmc, basename, mode);
    return (0);
}

int
kmdb_module_unloaded(kmdb_wr_unload_t *dur)
{
    mdb_var_t *v;

    if ((v = mdb_nv_lookup(&mdb.m_dmodctl, dur->dur_modname)) == NULL) {
        mdb_warn("unload for unrequested module %s\n",
            dur->dur_modname);
        return (0);
    }

    if (dur->dur_errno != 0) {
        mdb_warn("dmod %s failed to unload", dur->dur_modname);
        return (0);
    }

    kmc_free(MDB_NV_COOKIE(v));
    mdb_nv_remove(&mdb.m_dmodctl, v);

    return (1);
}

void
kmdb_module_unload_ack(kmdb_wr_unload_t *dur)
{
    if (dur->dur_modname != NULL)
        strfree(dur->dur_modname);
    mdb_free(dur, sizeof (kmdb_wr_unload_t));
}

/*
 * Called by the kmdb_kvm target upon debugger reentry, this routine checks
 * to see if the loaded dmods have changed.  Of particular interest is the
 * exportation of dmod symbol tables, which will happen during the boot
 * process for dmods that were loaded prior to kernel startup.  If this
 * has occurred, we'll need to reconstruct our view of the symbol tables for
 * the affected dmods, since the old symbol tables lived in bootmem
 * and have been moved during the kobj_export_module().
 *
 * Also, any ctf_file_t we might have opened is now invalid, since it
 * has internal pointers to the old data as well.
 */
void
kmdb_module_sync(void)
{
    mdb_var_t *v;

    mdb_nv_rewind(&mdb.m_dmodctl);
    while ((v = mdb_nv_advance(&mdb.m_dmodctl)) != NULL) {
        kmdb_modctl_t *kmc = MDB_NV_COOKIE(v);
        struct module *mp;

        if (kmc->kmc_state != KMDB_MC_STATE_LOADED)
            continue;

        mp = kmc->kmc_modctl->mod_mp;

        if ((mp->flags & (KOBJ_PRIM | KOBJ_EXPORTED)) &&
            !kmc->kmc_exported) {
            /*
             * The exporting process moves the symtab from boot
             * scratch memory to vmem.
             */
            if (kmc->kmc_symtab != NULL)
                mdb_gelf_symtab_destroy(kmc->kmc_symtab);

            kmc->kmc_symtab = mdb_gelf_symtab_create_raw(
                &kmc->kmc_ehdr, mp->symhdr, mp->symtbl, mp->strhdr,
                mp->strings, MDB_TGT_SYMTAB);

            if (kmc->kmc_mod->mod_ctfp != NULL) {
                ctf_close(kmc->kmc_mod->mod_ctfp);
                kmc->kmc_mod->mod_ctfp =
                    mdb_ctf_open(kmc->kmc_modname, NULL);
            }
            kmc->kmc_exported = TRUE;
        }
    }
}